Philippine authorities did something extraordinary on Tuesday: in the early morning hours they arrested a former senior security forces official implicated in serious human rights violations.

The arrest of Jovito Palparan, a retired army major general, marks a rare challenge to the country’s rampant impunity, which the government of President Benigno Aquino III has failed to adequately address.

Palparan is notorious for his alleged role in the abduction, torture, and enforced disappearance of University of the Philippines farmers’ rights activists Sherlyn Cadapan and Karen Empeño in 2006. There is also evidence linking his unit to the torture of Raymond Manalo, who later testified that he witnessed soldiers under Palparan’s command torture Cadapan and Empeño. Palparan, while an army brigade commander in Oriental Mindoro province, was also implicated in the abduction, torture, and murder of at least 29 leftist activists beginning in 2001. Palparan’s reputation for abuses made him a visible symbol of military brutality during the administration of former President Gloria Macapagal-Arroyo. During her State of the Nation Address in 2006, Arroyo publicly praised Palparan for his role in a military counter-insurgency campaign that had resulted in widespread human rights violations.

Palparan’s arrest gives Aquino an opportunity to make real progress on his long unfulfilled promise to end rights abuses in the Philippines. That means ensuring that Palparan goes to trial without interference from powerful elements in the military who might seek to protect him.

Above all, Aquino needs to follow-up Palparan’s arrest by bringing to justice other high-profile rights abusers, such as former Mayor Rey Uy, the alleged mastermind of the Tagum City “death squad.” That means jumpstarting the currently moribund judicial “superbody” Aquino created in 2012 to expedite the investigation and prosecution of extrajudicial killings. Failure to do so will be a betrayal of the victims of human rights violations who have looked to Aquino to end the status quo of impunity rather than perpetuate it.